Portable computing and communications devices including wireless devices, mobile devices, cellular telephones, personal digital assistants (“PDAs”), laptop computers, mobile data processing systems, portable global positioning system (“GPS”) navigation devices, and other data processing systems have limited battery life due to weight and size constraints that limit the size of the battery that can be incorporated within these devices, as well as the demands placed on the battery by the central processing unit (“CPU”), display, wireless transceiver, etc., of these devices. Typically, the power used to drive and light the display of a portable device is a significant drain on the device's battery. Such displays can be, for example, backlit as in the case of a transmissive liquid crystal display (“LCD”), or locally light-emissive in nature, as in the case of a light emitting diode (“LED”) technology based display. As such, a need exists for an improved method of reducing the power consumed by the displays of portable devices in order to improve the battery life of such devices.
Portable devices are used for numerous applications such as electronic mail, voice and data communications, word processing, mapping, navigation, computer games, etc. In general, these applications are launched by the system's operating system upon selection by a user from a menu or other graphical user interface (“GUI”). A GUI is used to convey information to and receive commands from users and generally includes a variety of GUI objects or controls, including icons, toolbars, drop-down menus, text, dialog boxes, buttons, and the like. A user typically interacts with a GUI by using a pointing device (e.g., a mouse) to position a pointer or cursor over an object and “clicking” on the object.
In addition to problems relating to limited battery life, another problem with these devices is the inability to effectively display detailed information for selected graphic objects when those objects are in the context of a larger image. A user may desire access to detailed information with respect to an object in order to closely examine the object, to interact with the object, or to interface with an external application or network through the object. For example, the detailed information may be a close-up view of the object or a region of a digital map image.
While an application may provide a GUI for a user to access and view detailed information for a selected object in a larger image, in doing so, the relative location of the object in the larger image may be lost to the user. Thus, while the user may have gained access to the detailed information required to interact with the object, the user may lose sight of the context within which that object is positioned in the larger image. This is especially so when the user interacts with the GUI using a computer mouse, keyboard, or keypad. The interaction may further distract the user from the context in which the detailed information is to be understood. This problem is an example of what is often referred to as the “screen real estate problem.”
The screen real estate problem generally arises whenever large amounts of information are to be displayed on a display screen of limited size. Known tools to address this problem include panning and zooming. While these tools are suitable for a large number of visual display applications, they become less effective where sections of the visual information are spatially related, such as in layered maps and three-dimensional representations, for example. In this type of information display, panning and zooming are not as effective as much of the context of the panned or zoomed display may be hidden.
The screen real estate problem is most apparent in devices having small display screens. In particular, portable devices such as cellular telephones, PDAs, and GPS navigation devices typically present usability challenges in making device functions efficiently and easily accessible, due to limited-sized displays and other device limitations such as small keyboards or small active input surfaces (e.g., touchscreens) for user input. Such problems are compounded by the increasing functionality of modem wireless devices, wherein new capabilities such as cameras, music players, and video players are being incorporated into these devices, making these devices increasingly complex. The end result is that the user typically faces difficulties in efficiently gaining a desired access to a particular device feature, or to particular content, while maintaining awareness of how to access other device capabilities or content.
Additionally, in computer graphics systems users often wish to exclude portions of an image presented to them on a display screen. This operation is called “cropping.” To perform a cropping operation or crop, a user typically selects two points to define a rectangle (e.g. top left and bottom right corners) enclosing a selected portion of the original image. The portion of the original image outside of the rectangle is then excluded or cropped and an image of the selected portion alone, that is, a cropped image, is presented to the user. One problem with conventional cropping methods is that a user may have difficulty selecting a desirable cropped image.